No description available.

Triclosan, 5-chloro-2-(2,4 dichlorophenoxy)phenol, is an anti-microbial additive in a plethora of Pharmaceutical and Personal Care Products (PPCPs) including, toothpastes, hand creams and soaps, and acne creams. Because many triclosan containing products are topical solutions that are readily washed down the drain, significant quantities of triclosan can be introduced to wastewater treatment systems and eventually, to surface waters. Consequently, triclosan has become a contaminant of concern. The reactions between triclosan and free chlorine have been examined previously; however, no kinetic data for these reactions have been reported for conditions typical of drinking water treatment. This investigation focused specifically on the kinetics of the triclosan and free available chlorine (FAC) reactions under drinking water treatment conditions. Triclosan readily reacted with free chlorine via a second-order reaction (first order with respect to each species). No significant temperature dependency was observed from 8 to 25 °C. The reaction stoichiometry was determined to be 1:1 (triclosan oxidized per free chlorine reduced and did not vary over the pH range examined (pH 4-12). However, the reaction rate coefficients exhibited a significant pH dependency. A model that incorporates the rate coefficients for the reactions between HOCl and both neutral and anionic forms of triclosan was generated to fit the experimental data. The anionic free chlorine species hypochlorite (OCl-) was determined to play an insignificant role in the overall rate of reaction, and therefore, only the reactions involving HOCl were incorporated into the model. Additionally, a hypothesized reaction mechanism was tentatively shown to fit the collected data and its strong pH dependency. / Master of Science

The antibacterial agent, triclosan, is widely used in many household personal care products, and it has recently been detected in wastewater treatment plant effluents and in source waters used for drinking water supply. Accordingly, the reactivity of triclosan with the disinfectants used in wastewater treatment and in the production of potable water is of interest. Monochloramine is used as an alternative disinfectant in drinking water treatment to minimize production of regulated disinfection by-products. This study examined the reactions between triclosan and monochloramine and involved analysis of monochloramine and triclosan decay and product formation under drinking water treatment conditions over a pH range of 6.5 to 10.5. Monochloramine decay in the presence of triclosan was measured relative to monochloramine auto-decomposition in the absence of triclosan using UV-VIS spectrophotometry. Experimental results showed that the monochloramine auto-decomposition intermediates, free chlorine and dichloramine, are responsible for a majority of the observed triclosan decay and product formation. A kinetic model for monochloramine auto-decomposition was modified to include terms and rate coefficients for the reactions of triclosan with monochloramine (<i>k</i> = 90.4 M^-1h^-1), free chlorine (<i>k</i> = 1.94&#215;10⁷ M^-1h^-1), and dichloramine (<i>k</i> = 2&#215;10⁵ M^-1h^-1), and was able to predict triclosan and monochloramine decay. It was determined that the reactions of dichloramine and free chlorine with triclosan were 10³ and 10⁵ times faster, respectively, than the reaction of monochloramine with triclosan. The products of these reactions, detected using GC-MS, included three chlorinated triclosan intermediates, 2,4-dichlorophenol, and 2,4,6-trichlorophenol. Low levels of chloroform were detected at pH values of 6.5 and 7.5. / Master of Science

Poultry skins and rendered poultry fat are by-products produced in excess at rendering plants. The use of low value by-products such as poultry collagen, from poultry skins, and fat to improve flavor and quality in dry pet food could be economically attractive. This study examined a poultry collagen coating as a protective barrier against oxidation in dry cat food made with rendered poultry fat. Collagen was extracted from chicken skins, dissolved in an acidic solution, applied to dry cat food and dried to form a surface film. Six treatments were examined: kibble, kibble with fat, kibble with collagen, kibble with fat and collagen, kibble with fat, BHA/BHT and collagen and kibble with fat, tocopherol and collagen. There were two storage conditions: ‘jungle condition’ (42°C and 83% relative humidity) and ‘ambient condition’ (21°C and 51% relative humidity). In ‘jungle conditions’, thiobarbituric acid reactive substances (TBARS) was measured over an eight-day period at day 0, 2, 4, 6, and 8. In ‘ambient conditions’, TBARS was measured over a thirty-day period at day 0, 7, 14, 21, and 30. Water activity and moisture contents were measured. There were significantly higher TBARS (P<0.05) for the control kibble at both storage conditions. There was significantly higher fat percentage (P<0.05) in all treatments with the additional fat coatings. Fatty acid compositions showed slight changes during storage. There were some changes in the aroma profile of the kibble with fat treatment having musty, moldy and plastic aromas at both storage conditions. The volatile aromas might be an indication of oxidation in the poultry fat. / Master of Science

Typescript (photocopy). / Digitized by Kansas Correctional Industries

By-products and mortalities from aquaculture have often posed significant challenges to the industry because of their low value resulting in high costs and environmental impact from their disposal. However increasing interest is being expressed in their utilisation to add value to the aquaculture industry and provide synergies with industries which had previously been in competition with aquaculture. Current and prospective processing by-product and farm mortality utilisation strategies were reviewed along with regulations and standards which aim to control their use and protect against human and animal health hazards. The role of aquaculture and fishery by-products in the supply of fishmeal was investigated and it was found that both sectors had the potential to contribute to increasing global supply. There were significant quantities of processing by-products identified which could be directed to fishmeal manufacture but there were also significant amounts of fish production which were not being processed in some regions and could also add to supplies. Processing by-products from aquaculture species often exceed 50% of the production by mass and therefore their efficient utilisation is of significant importance to the overall performance of the value chain. Their utilisation strategies are diverse and in some circumstances offer the possibility to add significant value. Life Cycle Assessment (LCA) is increasingly being used to inform decision makers and consumers about the environmental performance of goods and services to make choices on best practices and informative decisions on purchasing choices. Current methodology in LCA was critiqued and developed to be used for identifying disproportionate impacts from by-product industries and comparative assessment of the eco-efficiency of value chains from Thai shrimp, Vietnamese Pangasius catfish and Scottish salmon aquaculture. New LCA methodology was developed assessing the eco-efficiency of co-products as a whole and in relation to a tonne of edible yield. Measuring the impact of the by-product industry in relation to their edible yield gave different results to measuring their eco-efficiency between the three study species. It was found that the Thai shrimp value chain was the most eco-efficient when by-products were directed to chitosan and hydrolysate manufacture, but production of the salmon was the least impacting between the species in terms of edible yield. Pangasius was the most environmentally impacting of the three species value chains using both methods. It was also found that the upstream impacts of fish and shrimp production, especially feed manufacture, contributed most to the environmental impact in most circumstances, using both economic and mass allocation. Although the methodology produced interesting results, there were some drawbacks and the data sets also had several gaps which led to some assumptions, which could have skewed the results and interpretation. The cause of mortality for five aquaculture species in five countries and their subsequent utilisation was investigated. It was found that extensive systems were more prone to mortality than intensive systems in many cases. There was a wide range of strategies for mortality utilisation. In countries where by-product industries existed, farmers were often able to sell some of their mortality losses but in other areas, disposal could create health and biosecurity hazards. In conclusion, it was found that both by-products and aquaculture mortalities could be utilised effectively and that the additional impact from their use was low in proportion to the rest of the value chain.

The research pursued relates to the establishment of interrelationship between various factors affecting chitin extraction, and combination of optimum levels of factors required to maximize the yield of chitin extraction. Optimization of chitin extraction was carried out using crab, lobster, and shrimp solid wastes. The study was divided into two stages: (a) optimization of chitin extractability with respect to particle size; (b) optimization of demineralization and deproteinization stages in lobster chitin extraction using Response Surface Methodology. Particle size had a significant effect on crab and lobster chitin extractability; a particle size of 2.0mm gave the highest yield in chitin extraction. The mean yield of chitin from crab and lobster at particle size of 2.0mm were 28.8% and 23.2%, respectively. Shrimp chitin extractability was not affected by particle size with the mean yield being 25.2%. Response Surface Methodology was used to determine simultaneous effects of (a) concentration of extractant; (b) shell:extractant ratio; (c) temperature of extraction; and (d) time of extraction on deproteinization and demineralization stages of chitin extraction and hence yield of chitin. All variables had an effect on demineralization and deproteinization yields. Maximum demineralization was predictable by a multi-factor model consisting of a combination of concentration of HCl, shell:extractant ratio, temperature and time of extraction. (Abstract shortened by UMI.)

Chitin is a polysaccharide found in abundance in the shell of crustaceans. In this study, chitin was first extracted from shrimp waste material previously demineralized, using proteolytic enzymes, i.e., chymotrypsin and papain. The conditions used for the deproteinization were optimized with respect to 3 factors, viz., pH, temperature, and enzyme to waste (E/W) ratio, using response surface methodology (RSM). / In a second part of the study, chitosan was prepared from chitin by partial deacetylation and its capacity to preserve whole and headless fresh shrimps was evaluated. The shrimps (Pandalus borealis) were dipped in chitosan (1 and 2% w:v), and stored on ice. Chemical indicators such as pH, drip loss, total volatile bases (TVB), nucleotide degradation, and sensory indicators of appearance (including melanosis) and odor, as well as total microbial counts were monitored during 20 days. / As a third and final part, the antimicrobial properties of chitosan were evaluated using several microorganisms implicated in food spoilage and/or food poisoning outbreaks, especially those associated with fish and seafood products. Chitosan prepared from crab offal and used in the previous study on shrimp preservation was compared with commercially available chitosan from Sigma Chemical Co. (St-Louis, MO). (Abstract shortened by UMI.)

The shrimp processing industry has to deal with the ever-growing costs associated with the disposal of their residuals. However, investigation into the possibility of making high-value biopolymers (chitin and chitosan) from this waste shows significant potential for developing a chitin and chitosan industry in Quebec. / The pharmaceutical and medicine industry is the target market for high-grade chitosan. Based on the related data of cellulose derivatives (the closest substitute for chitosan), the Bass model was used to forecast the sales of high-grade chitosan in Quebec. It is estimated that the potential market for chitosan in Quebec is worth 37 million dollars (in 1999 prices) cumulative for the next 20 year period and 59 million for Canada. In the first year of marketing chitosan, sales in Canada (high-grade) are expected to reach $3.2 million from which $1.55 million is expected to be generated in Quebec. (Abstract shortened by UMI.)

No description available.